1. Field of the Invention
The present invention relates to image equipment having image forming elements such as an image sensor element or a display element, and also to a vibrating device designed to vibrate the dust-screening member that is arranged at the front of each image forming element of such an image equipment.
2. Description of the Related Art
As image equipment having image forming elements, there is known an image acquisition apparatus that has an image sensor element configured to produce a video signal corresponding to the light applied to its photoelectric conversion surface. Also known is an image projector that has a display element, such as liquid crystal element, which displays an image on a screen. In recent years, image equipment having such image forming elements have been remarkably improved in terms of image quality. If dust adheres to the surface of the image forming element such as the image sensor element or display element or to the surface of the transparent member (optical element) that is positioned in front of the image forming element, the image produced will have shadows of the dust particles. This makes a great problem.
For example, digital cameras of called “lens-exchangeable type” have been put to practical use, each comprising a camera body and a photographic optical system removably attached to the camera body. The lens-exchangeable digital camera is so designed that the user can use various kinds of photographic optical systems, by removing the photographic optical system from the camera body and then attaching any other desirable photographic optical system to the camera body. When the photographic optical system is removed from the camera body, the dust floating in the environment of the camera flows into the camera body, possibly adhering to the surface of the image sensor element or to the surface of the transparent member (optical element), such as a lens, cover glass or the like, that is positioned in front of the image sensor element. The camera body contains various mechanisms, such as a shutter and a diaphragm mechanism. As these mechanisms operate, they produce dust, which may adhere to the surface of the image sensor element as well.
Projectors have been put to practical use, too, each configured to enlarge an image displayed by a display element (e.g., CRT or liquid crystal element) and project the image onto a screen so that the enlarged image may be viewed. In such a projector, too, dust may adhere to the surface of the display element or to the surface of the transparent member (optical element), such as a lens, cover glass or the like, that is positioned in front of the display element, and enlarged shadows of the dust particles may inevitably be projected to the screen.
Various types of mechanisms that remove dust from the surface of the image forming element or the transparent member (optical element) that is positioned in front of the image sensor element, provided in such image equipment have been developed.
In a vibrating device disclosed in, for example, US2008/0018775A1, an optical low-pass filter constituted of first to third groups of optical members, a piezoelectric element, an image acquisition element and the like are incorporated in an image acquisition unit. That is, a vibration transmission member having a substantially L-shaped section is bonded and fixed to an upper side of the first group of optical members. An urging force transmission member having a substantially L-shaped section is bonded and fixed to a facing lower side of the first group of optical members. Moreover, a receiving portion for receiving the piezoelectric element is formed in an upper side of a frame portion of a low-pass filter holding member which holds the low-pass filter. The piezoelectric element has one end surface which is fixed to the frame portion with an adhesive or the like and held so that an expansion/contraction direction due to the application of a voltage becomes an orthogonal direction (a camera upward/downward direction) with respect to an image acquisition optical axis. Furthermore, vibration in the orthogonal direction with respect to the image acquisition optical axis is applied to the first group of optical members as a dust-screening member by the piezoelectric element, to remove foreign matters of dust and the like which adhere to the surfaces of the optical members of the first group.